Indexing stop of valve stem

ABSTRACT

In a conventional valve assembly having a valve body, a valve member disposed in the body, and a rotatable valve stem journaled in the body, and a rotatable valve stem journaled in the body and connected at the inner end thereof to the valve member and extending through the body with the outer end thereof having a pair of parallel flat surfaces formed thereon, an apparatus carried by the body for limiting the rotation of the valve stem so that the valve member will stop at either a fully closed or open position. In one form of the apparatus the outer end of the valve stem extends through an aperture formed in a plate which is seated in a groove formed in the valve body. Diametrically opposed shoulders extend radially inward from the aperture wall to engage the flat surfaces of the stem. In another form, the plate is secured to the valve body by means of two pins extending outwardly from the valve body through matching holes formed in the plate. In yet another form, the plate is combined with a means for providing a seal about the stem. Retaining means and cover means for the apparatus are also disclosed.

United States Patent ['1 Searamucci INDEXING STOP OF VALVE STEMInventor: Domer Scaramuccl, 3245 S. Hattie,

Oklahoma City, Okla. 73129 Filed: July 1 1971 Appl. No.: 158,777

U.S. Cl. 251/288 Int. Cl. F16k 51/00 Field of Search 251/286, 287, 288;

References Cited UNITED STATES PATENTS 11/1959 Freed 251/288 12/1954Barksdale ..25l/286X 8/1945 Franck ..'251/286 Primary Examiner-Henry T.Klinksiek 57 ABSTRACT In a conventional valve assemblyhaving a valvebody,

3,743,243 July 3, 1973 a valve member disposed in the body, and arotatable valve stem joumaled in the body, and a rotatable valve stemjournaled in the body and connected at the inner end thereof to thevalve member and extending through the body with the outer end thereofhaving a pair of parallel flat surfaces formed thereon, an apparatuscarried by the body for limiting the rotation of the valve stem so thatthe valve member will stop at either a fully closed or open position. Inone form of the apparatus the outer end of the valve stem extendsthrough 14 Claims, 9 Drawing Figures 54 94 95 96 92 M M 74 5? 2i 7870 7694 7g W 58 42 40 55 M 60 L2 44 I I yd M 7 5e 76 22 4o 28 it M 50 9 14,,56

k a k m 3 4'6 H INDEXING STOP OF VALVE STEM BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates generally toimprovements in valves, and more particularly, but not by way oflimitation, to apparatus for limiting the rotation of a valve stem.

2. Description of the Prior Art It is common practice to have anindexing mechanism on any type of rotary valve so that the valve memberwill stop in either a fully closed or a fully open position when turnedby the operator. The most common practice is to provide a lug on aportion of the valve handle which alternately engages one of a pair ofspaced lugs formed on the upper end of the neck of the valve body. Sucha construction is expensive because of the precise positioning requiredof the lugs. Further, the lugs are frequently broken off, and the areabetween the lugs is exposed to foreign material, such as dirt and ice,so that the lugs will frequently not be engaged when the valve member isturned to properly position the valve member in either an open or closedposition. Frequently, the introduction of foreign material between thelugs prevents the turning of the valve member at all.

When the lug on the valve handle engages the respective lug formed onthe neck of the valve body, continued application of turning force tothe valve handle causes the valve stem to be biased away from the lug onthe body thereby creating undesirable loading on the stem and the stemsealing means. This situation can lead to premature stem seal failureand accelerated valve wear.

SUMMARY OF THE INVENTION The present invention contemplates a novelapparatus for limiting the rotation of a valve stem in a valve whichincludes a valve body having an upstream end face, a downstream endface, and a bore extending therethrough intersecting the end faces. Avalve member is disposed within the bore of the valve body intermediatethe end faces and is rotatable from a position wherin the bore is opento a position wherein the bore is closed. A valve stem extends throughthe valve body and is connected at the inner end thereof to the valvemember for rotation thereof. A pair of parallel flat surfaces is forrnedon the outer end of the valve stem. Means for limiting the rotation ofthe valve stem and the valve member connected thereto between the openand closed positions includes a substantially flat plate rigidly securedto the outer portion of the valve body. An aperture is formed in theflat plate through which the outer end of the valve stem extends. A pairof diametrically opposed shoulders are formed on the inner periphery ofthe aperture and extend radially inward therefrom a sufficient distanceto interfere with the parallel flat surfaces of the valve stem therebylimiting the rotation thereof.

An object of the present invention is to provide an apparatus forlimiting the rotation of a valve stem and the valve member connectedthereto which is easily fabricated and installed.

Another object of the present invention is to provide an apparatus forlimiting the rotation of a valve stem and the valve member connectedthereto which effectively prevents the entrance of foreign matter whichwould foul the precise indexing of the valve stem.

A further object of the present invention is to provide an apparatus forlimiting rotation of a valve stem and the valve member connected theretowhich performs a sealing function around the valve stem.

A still further object of the present invention is to provide anapparatus for limiting the rotation of a valve stem and the valve memberconnected thereto which is economical in construction and operation.

Further objects and advantages of the present invention will be evidentfrom the following detailed description when read in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical cross-sectionalview of a ball valve constructed in accordance with the presentinvention.

FIG. 2 is a fragmentary cross-sectional view taken along line 2-2 ofFIG. 1 and illustrating the valve operating member in the closedposition.

FIG. 3 is a fragmentary cross-sectional view similar to FIG. 2illustrating the valve operating member in the open position.

FIG. 4 is a fragmentary vertical cross-sectional view of anotherembodiment of ball valve also constructed in accordance with the presentinvention.

FIG. 5 is a fragmentary cross-sectional view taken along line 5-5 ofFIG. 4.

FIG. 6 is a fragmentary plan view taken along line 6-6 of FIG. 4.

FIG. 7 is a fragmentary vertical cross-sectional view of anotherembodiment of ball valve constructed in accordance with the presentinvention.

FIG. 8 is a top view of the stop plate illustrated in FIG. 7.

FIG. 9 is a bottom view of the stop plate illustrated in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings and toFIGS. 1, 2 and 3 in particular, shown therein and generally designatedby the reference character 10 is a ball valve constructed in accordancewith the invention. As illustrated therein, the ball valve 10 includes avalve body 12 having a passageway or bore 14 extending therethrough. Atransverse passageway or bore 16 of circular crosssection extendsthrough the wall of the valve body 12 intersecting the passageway 14 forpurposes that will be described more fully hereinafter. The transversebore 16 is provided with a counter bore adjacent its intersection withthe passageway 14 providing a planar surface 18 in the valve body 12.

A pair of identically constructed seal rings 20 and 22 are disposed inthe opposite ends of the ball valve 10 and are in engagement with anupstream end face 24 and a downstream end face 26, respectively, on thevalve body 12. The seal ring 20 includes an end face 28 that is inengagement with the inner face 30 of a standard pipe flange 32. The sealring 22 includes an end face 34 that is in engagement with the innerface 36 of a standard pipe flange 38. The seal rings 20 and 22 arepreferably constructed from a relatively rigid material.

A plurality of threaded fasteners 40 extend through the flanges 32 and38, respectively, and are provided with threaded nuts 42 and 44 that arethreaded onto the threaded fasteners 40 to move the flanges 32 and 38relatively toward each other.

Located within the passageway 14 in the valve body 12 is a valve memberor ball 46 having a flow port 48 extending therethrough. The exteriorsurface of the valve ball 46 is provided with a rectangular recess orgroove 50 sized to receive the rectangular end or tongue 52 of a valveoperating member or stem 54.

The valve operating member 54 of substantially circular cross-sectionextends through the transverse bore 16 and includes a flange 56 formedthereon adjacent the rectangular end 52 thereof. The flange 56 ispositioned adjacent the planar surface 18 of the valve body 12, and isseparated therefrom by a bearing washer 57 encircling the valveoperating member 54, thereby limiting the upward movement of the valveoperating member 54 in the passageway 16 of the valve body 12. Thebearing washer S7 is preferably constructed of a relatively resilientmaterial such as Teflon. An O-ring seal 58 is located in an annulargroove 60 encircling the valve operating member 54. The seal 58sealingly engages both the valve operating member 54 and the valve body12 in the transverse bore 16.

The end of the valve operating member 54 extending from the valve body12 is provided with a pair of parallel flat surfaces 62 and 64 formedthereon and extending from within the valve body 12 to the outer end 66of the valve operating member 54. A recess is formed in the valve body12 adjacent the valve operating member 54 forming a planar surface 68normal to the longitudinal axis of the valve operating member or stem 54and further forming a pair of parallel walls 70 and 72 substantiallynormal to the planar surface 68. It should be noted that the flatsurfaces 62 and 64 extend into the valve body 12 to a point slightlybelow the depth of the planar surface 68. A rectangular plate 74 havinga substantially circular aperture 76 formed therein, is positioned onthe planar surface 68 encircling the valve operating member 54 whichextends through the aperture 76 thereof. The plate 74 is prevented fromrotating with the valve operating member 54 by the engagement of theparallel edges 78 and 80 thereof, respectively, with the walls 70 and 72of the recess. A pair of diametrically opposed stops or shoulders 82 and84 are formed within the aperture 76 of the plate 74 and extend radiallyinward therefrom. The stops 82 and 84 are sized and shaped such that theflat surfaces 62 and 64 of the valve operating member 54 will be engagedthereby thus limiting the rotation of the valve operating member 54 to90.

An interrupted annular groove 86 is formed in the cylindrical segments88 and 90 of the valve operating member 54 adjacent the upper side 92 ofthe plate 74. A spring type retaining ring 94 is positioned in thegroove 86 and extends radially outward therefrom over the upper side 92of the rectangular plate 74 in assembled operating position. A dust cap96, having an aperture 98 formed therein, encircles the upper endportion of the valve operating member 54 and covers the retaining ring94. The aperture 98 is sized and shaped to conform to the exterior shapeof the valve operating member and is adapted to rotate therewith. Thedust cap 96 may be conveniently formed of synthetic resin material suchas Nylon and may be suitably inscribed with words or symbols indicatingthe position of the valve ball 46.

It should be noted that the plate 74 may be come niently formed of ametal stamping. The shape of the plate 74 need not necessarily berectangular, although this shape simplifies the forming of the matingrecess in the valve body 12, but may take on any number of noncircularshapes which would prevent the rotation of the plate 74 with the valveoperating member 54.

DESCRIPTION OF tHE EMBODIMENT OF FIGS. 4, 5 AND 6 The fragmentaryvertical cross-sectional view of FIG. 4 illustrates a modified form ofball valve that is generally designated by the reference character 10aand is also constructed in accordance with the present invention. Manyof the components previously described with respect to the ball valve 10are incorporated in the ball valve 10a and will, therefore, bedesignated by the same reference characters. As illustrated in FIG. 4, aplanar surface 100 is formed on the slightly modified valve body 120adjacent the valve operating member 54 and normal to the longitudinalaxis thereof. A pair of guide pins 102 and 104 are fixedly secured tothe valve body 12a in parallel alignment with the longitudinal centerline of the valve operating member 54, and extend upwardly a distancefrom the planar surface 100. An indexing plate 106, having asubstantially circular aperture 108 formed therein and having a pair ofclear holes 110 and 112 also formed therein, is positioned on the planarsurface 100 encircling the valve operating member 54. The clear holes 110 and 112 are sized and positioned in the indexing plate 106 such thatthe guide pins 102 and 104, respectively, slidingly pass therethrough tosecure the indexing plate 106 on the planar surface 100 therebypreventing any sliding movement of the indexing plate 106 along thesurface 100. A pair of diametrically opposed stops or shoulders 1 14 and116 are formed within the aperture 108 of the indexing plate 106 andextend radially inward therefrom. The stops 114 and 116 are sized andshaped such that the flat surfaces 62 and 64 of the valve operatingmember 54 will be engaged thereby thus limiting the rotation of thevalve operating member 54 to 90.

A dust cover plate 118, having an aperture 120 formed therein, encirclesthe upper end portion of the valve operating member 54 and is positionedadjacent the upper side 122 of the indexing plate 106. The aperture 120is sized and shaped to conform to the exterior shape of the valveoperating member 54 which extends therethrough and is adapted to rotatetherewith. The dust cover plate 118 may be conveniently formed ofstamped sheet metal or may be molded of a relatively rigid material suchas Nylon or Delrin.

An interrupted annular groove 86 is formed in the cylindrical segments88 and 90 of the valve operating member 54 adjacent the upper side 124of the dust cover plate 118. A spring type retaining ring 94 ispositioned in the groove 86 and extends radially outward therefrom overthe upper side 124 of the dust cover plate 118 thereby retaining thevalve operating member 54, the indexing plate 106 and the dust coverplate 118 in assembled operating position.

It should be noted that the indexing plate 106 may be convenientlyformed of a metal stamping or other suitable material. lt should also benoted that the guide pins 102 and 104 should preferably extend above theplanar surface 100 a distance substantially equal to the thickness ofthe indexing plate 106 thereby providing a flush surface on the upperside 122 vertical sectional DESCRIPTION OF THE EMBODIMENT OF FIGS. 7,

8 AND 9 The fragmentary vertica-sectional view of FIG. 7 illustratesanother modified form of ball valve that is generally designated by thereference character 10b and is also constructed in accordance with thepresent invention. As shown therein, the valve body has been modifiedand is designated by the reference character 12b. A counterbore 126 isformed in the upper end of the slightly modified transverse passageway16b and forms an upwardly facing annular shoulder 128. A planar surface130 is formed on the upper portion of the valve body 12b normal to thelongitudinal center line of the slightly modified valve operating member54b. A recess 132 is formed in the upper end of the valve body 12badjacent the valve operating member 54b and forms a planar surface 134parallel to the planar surface 130. The recess 132 is preferably in theform of a transverse groove having parallel side walls 136 and 138 whichinterconnect the planar surfaces 130 and 134.

A combination indexing plate and packing gland follower 140 is disposedin the recess 132 and th7 counterbore 126. A substantially circularaperture 142 is formed in the plate 140 as is more clearly illustratedin FIGS. 8 and 9. The aperture 142 is sized such that the upper end 66of the valve operating member 54b extends therethrough. A pair ofdiametrically opposed projections or shoulders 144 and 146 are sized andpositioned in the aperture 142 such that they engage the fiat surfaces62 and 64 of the valve operating member 54b to limit the rotationthereof to 90. The upper portion 148 of the plate 140 is characterizedby a pair of parallel edges 150 and 152 which engage the side walls 136and 138, respectively, of the recess 132 to prevent the rotation of theplate 140 with the valve operating member 54b. The lower portion of theplate 140 is characterized by an annular gland follower portion 154which encircles the portion of the valve operating member 54b below thefiat surfaces 62 and 64 and extends downwardly between the valveoperating member 54b and the counterbore 126. The end face 156 of thegland follower portion 154 engages an annular sealing member or packinggland 158 encircling the valve operating member 54b which is confined bythe annular wall 128, the counterbore 126 and the valve operating member54b. It should be noted that the projections or shoulders 144 and 146 donot extend to the full depth of the plate 140 but are restricted to theupper portion 148 thereof as best shown in FIG. 7.

A bonnet plate 160 is positioned adjacent the upper end of the valvebody 12b with the upper end 66 of the valve operating member 54bextending through a circular aperture 162 formed therein. The diameterof the aperture 162 is substantially equal to the diameter of thecircular portion of the aperture 142 formed in the plate 140. The bonnetplate 160 is secured to the valve body 12b by a pair of cap screws 164and 166 passing therethrough and threaded into the valve body 12b. Thebonnet plate 160 engages the upper face 168 of the plate 140, and, bytightening the cap screws 164 and 166, the plate 140 is drawn downwardlyinto the valve body 12b. As the plate 140 is forced downwardly by thebonnet plate 160, the end face 156 of the gland follower portion 154compresses the confined packing gland 158 thereby providing a sealbetween the valve body 12b and the valve operating member 54b.

A dust cover plate 118 as described above is positioned about the upperend portion of the valve operating member 54b adjacent the upper side170 of the bonnet plate 160. The dust cover plate 118 is secured inposition by the previously described retaining ring 94 positioned in theinterrupted annular groove 86 formed in the valve operating member 54b,which also rotatably secures the valve operating member 54b to the valvebody 12b in assembled operating position.

It should be noted that any loading of the plate resulting from theengagement of the projections 144 and 146 thereof by the flat surfaces62 and 64 of the valve operating member 54b is transmitted to the valvebody 121; by the edges and 152 of the plate 140 to the adjacent sidewalls 136 and 138, respectively, formed in the valve body 12b. The capscrews 164 and 166 are loaded only in tension and never experience anyshear stress due to external force applied to the valve operating member54b.

From the foregoing detailed description of the vari-' ous forms ofapparatus for limiting the rotation of a valve operating member or stemit can be readily seen that the present invention provides apparatuswhich is easily fabricated and installed and which effectively preventsthe entry of foreign matter which might foul the precise indexing of thevalve stem or operating member. It may further be seen that thediametrically opposed stem stops or shoulders eliminate undesirablebiasing of the valve operating member or stem within the valve bodythereby providing perfect alignment within the stem packing chamber orpassageway for dependable, trouble free stem and sealing service.

Changes may be made in the construction and arrangement of parts orelements of the various embodiments as disclosed herein withoutdeparting from the spirit and scope of the invention.

What is claimed is: 1. A valve comprising: a valve body having anupstream end face, a downstream end face, and a bore extendingtherethrough intersecting the end faces; a valve member disposed withinthe bore of said valve body intermediate the end faces and rotatablefrom a position wherein the bore is open to a position wherein the boreis closed; a valve stem extending through said valve body and connectedat the inner end thereof to said valve member for rotation thereof, andhaving a pair of parallel flat surfaces formed on the outer end portionthereof; v means for limiting the rotation of said valve stem and saidvalve member connected thereto between the open and closed positions,including:

an indexing plate rigidly secured to the outer portion of said valvebody and having an aperture formed therein through which the outer endportion of said valve stem extends, and

a pair of diametrically opposed shoulders formed on the inner peripheryof the aperture and extending radially inward therefrom to engage theparallel flat surfaces of said valve stem thereby limiting the rotationthereof; and

cover means positioned on the outer end portion of said valve stemadjacent said indexing plate for preventing the introduction of foreignmatter between the valve stem and the indexing plate. 2. The valve asdefined in claim 1 wherein said indexing plate is matingly received in arecess formed in the outer portion of said valve body whereby saidindexing plate is prevented from rotating about the axis of said valvestem.

3. The valve as defined in claim 1 wherein said index- 4. The valve asdefined in claim 2 wherein said index- 1 ing plate is secured in saidrecess by retaining means engaging said valve stem.

5. The valve as defined in claim 4 wherein said cover means ispositioned on said valve stem intermediate said indexing plate and saidretaining means.

6. The valve as defined in claim 4 wherein said cover means ispositioned on said valve stem intermediate said retaining means and theouter end of said valve stem.

7. A valve comprising: a valve body having a upstream end face, adownstream end face, a bore extending therethrough intersecting the endfaces, and an aperture formed therein intersecting the bore; a valvemember disposed within the bore of said body intermediate the end facesand rotatable from a position wherein the bore is open to a positionwherein the bore is closed; a valve stem journaled in the aperture ofsaid valve body and connected at the inner end thereof to said valvemember for rotation thereof, and having a pair of parallel flat surfacesformed on the outer end portion thereof; means for limiting rotation ofsaid valve stem, including: an indexing plate, having an upper portionand a lower portion, rigidly secured to the outer portion of said valvebody and having a substantially circular opening formed therein throughwhich opening the outer end portion of said valve stem extends; and

a pair of diametrically opposed projections formed on the inner wall ofthe opening in said indexing plate and extending radially inwardtherefrom to engage the flat surfaces of said valve stem and limit therotation thereof;

a cover disposed on the outer end portion of said valve stem adjacentsaid indexing plate;

a counterbore formed in the aperture of said valve body intersecting theouter portion of said valve body;

an annular extension formed on the lower portion of the indexing platecoaxial with the opening formed therein, said extension being disposedin said counterbore; and

an annular sealing member encircling said valve stem and disposed insaid counterbore and sealingly engaged by said annular extension,thereby forming a seal between said stem and said valve body. 8. Thevalve as defined in claim 7 wherein a noncircular recess is formed inthe outer portion of said valve body into which recess the upper portion-of said indexing plate is matingly received, whereby said indexingplate is prevented from rotating about the axis of said valve stem.

9. The valve as defined in claim 8 characterized fur-' ther to include:

means for retaining said annular end face in sealing engagement withsaid annular sealing member.

10. The valve as defined in claim 9 characterized further to include:

an interrupted annular groove formed about the outer end portion of saidvalve stem; and

a retaining ring disposed in said annular groove for axially positioningsaid valve stem in the aperture of said valve body.

11. The valve as defined in claim 10 wherein said cover is disposed onsaid valve stem intermediate said retaining ring and said indexingplate.

12. The valve as defined in claim 1 wherein said plate is secured tosaid valve body by at least two guide pins, said guide pins beingfixedly secured to said valve body and extending through matching guideholes formed in said plate, said plate being retained on said guide pinsby a retaining ring engaging said valve stem, and wherein said cover isdisposed on said valve stem intermediate said retaining ring and saidindexing plate.

13. A valve comprising:

a valve body having an upstream end face, a downstream end face, and abore extending therethrough intersecting the end faces;

a valve member disposed within the bore of said valve body intermediatethe end faces and rotatable from a position wherein the bore is open toa position wherein the bore is closed;

a valve stem extending through said valve body and connected at theinner end thereof to said valve member for rotation thereof and having apair of parallel flat surfaces formed on the outer end portion thereof;

a recess formed in the outer portion of said valve body adjacent saidvalve stem, said recess forming a planar surface substantially normal tosaid valve stem and a pair of spaced walls intersecting the planarsurface and substantially normal thereto;

an indexing plate disposed on the planar surface in said recess, saidindexing plate having a pair of spaced edges matingly engaging thespaced walls of said recess and having an aperture formed thereinthrough which aperture the outer end portion of said valve stem extends;and

a pair of diametrically opposed shoulders formed on the wall of theaperture and extending parallel flat surfaces of said valve stem therebylimiting the rotation thereof.

14. The valve as defined in claim 13 wherein said indexing plate issecured in said recess by retaining means engaging said valve stem.

1 t t 1 b P0405? UNITED STATES PATENT OFFICE s9 CERTIFICATE OFCORRECTION iatent No. 3,743,243 Dated July 3 L213 Inventor(g) DomerScaramucci It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

r- 001. 5 line I, delete "vertical sectional and insert -thereof.

Col 5 line 5 "vertical-sectional" should be vertical-cross-* sectional-.

Col 5 line 25 "th7" should be --the-.

Col 5 line 58 "aperture 142" should be --aperture 144-- Col 7 line 12 inClaim 3 before the word "plate" insert indexing- Col 7 line 11,"indexing" should be cancelled v and inserted after "said" in line l2.

Signed and sealed this 22nd day of January 19714.;

Attestz,

EDWAfiD M.P"LET HER, R. "RENE D. TEGTMEYER Attesting Officer ActingCommissioner of Patents

1. A valve comprising: a valve body having an upstream end face, adownstream end face, and a bore extending therethrough intersecting theend faces; a valve member disposed within the bore of said valve bodyintermediate the end faces and rotatable from a position wherein thebore is open to a position wherein the bore is closed; a valve stemextending through said valve body and connected at the inner end thereofto said valve member for rotation thereof, and having a pair of parallelflat surfaces formed on the outer end portion thereof; means forlimiting the rotation of said valve stem and said valve member connectedthereto between the open and closed positions, including: an indexingplate rigidly secured to the outer portion of said valve body and havingan aperture formed therein through which the outer end portion of saidvalve stem extends, and a pair of diametrically opposed shoulders formedon the inner periphery of the aperture and extending radially inwardtherefrom to engage the parallel flat surfaces of said valve stemthereby limiting the rotation thereof; and cover means positioned on theouter end portion of said valve stem adjacent said indexing plate forpreventing the introduction of foreign matter between the valve stem andthe indexing plate.
 2. The valve as defined in claim 1 wherein saidindexing plate is matingly received in a recess formed in the outerportion of said valve body whereby said indexing plate is prevented fromrotating about the axis of said valve stem.
 3. The valve as defined inclaim 1 wherein said indexing plate is secured to said valve body by atleast two guide pins, said guide pins being fixedly secured to saidindexing valve body and extending through matching guide holes formed insaid plate.
 4. The valve as defined in claim 2 wherein said indexingplate is secured in said recess by retaining means engaging said valvestem.
 5. The valve as defined in claim 4 wherein said cover means ispositioned on said valve stem intermediate said indexing plate and saidretaining means.
 6. The valve as defined in claim 4 wherein said covermeans is positioned on said valve stem intermediate said retaining meansand the outer end of said valve stem.
 7. A valve comprising: a valvebody having a upstream end face, a downstream end face, a bore extendingtherethrough intersecting the end faces, and an aperture formed thereinintersecting the bore; a valve member disposed within the bore of saidbody intermediate the end faces and rotatable from a position whereinthe bore is open to a position wherein the bore is closed; a valve stemjournaled in the aperture of said valve body and connected at the innerend thereof to said valve member for rotation thereof, and having a pairof parallel flat surfaces formed on the outer end portion thereof; meansfor limiting rotation of said valve stem, including: an indexing plate,having an upper portion and a lower portion, rigidly secured to theouter portion of said valve body and having a substantially circularopening formed therein through which opening the outer end portion ofsaid valve stem extends; and a pair of diametrically opposed projectionsformed on the inner wall of the opening in said indexing plate andextending radially inward therefrom to engage the flat surfaces of saidvalve stem and limit the rotation thereof; a cover disposed on the outerend portion of said valve stem adjacent said indexing plate; acounterbore formed in the aperture of said valve body intersecting theouter portion of said valve body; an annular extension formed on tHelower portion of the indexing plate coaxial with the opening formedtherein, said extension being disposed in said counterbore; and anannular sealing member encircling said valve stem and disposed in saidcounterbore and sealingly engaged by said annular extension, therebyforming a seal between said stem and said valve body.
 8. The valve asdefined in claim 7 wherein a noncircular recess is formed in the outerportion of said valve body into which recess the upper portion of saidindexing plate is matingly received, whereby said indexing plate isprevented from rotating about the axis of said valve stem.
 9. The valveas defined in claim 8 characterized further to include: means forretaining said annular end face in sealing engagement with said annularsealing member.
 10. The valve as defined in claim 9 characterizedfurther to include: an interrupted annular groove formed about the outerend portion of said valve stem; and a retaining ring disposed in saidannular groove for axially positioning said valve stem in the apertureof said valve body.
 11. The valve as defined in claim 10 wherein saidcover is disposed on said valve stem intermediate said retaining ringand said indexing plate.
 12. The valve as defined in claim 1 whereinsaid plate is secured to said valve body by at least two guide pins,said guide pins being fixedly secured to said valve body and extendingthrough matching guide holes formed in said plate, said plate beingretained on said guide pins by a retaining ring engaging said valvestem, and wherein said cover is disposed on said valve stem intermediatesaid retaining ring and said indexing plate.
 13. A valve comprising: avalve body having an upstream end face, a downstream end face, and abore extending therethrough intersecting the end faces; a valve memberdisposed within the bore of said valve body intermediate the end facesand rotatable from a position wherein the bore is open to a positionwherein the bore is closed; a valve stem extending through said valvebody and connected at the inner end thereof to said valve member forrotation thereof and having a pair of parallel flat surfaces formed onthe outer end portion thereof; a recess formed in the outer portion ofsaid valve body adjacent said valve stem, said recess forming a planarsurface substantially normal to said valve stem and a pair of spacedwalls intersecting the planar surface and substantially normal thereto;an indexing plate disposed on the planar surface in said recess, saidindexing plate having a pair of spaced edges matingly engaging thespaced walls of said recess and having an aperture formed thereinthrough which aperture the outer end portion of said valve stem extends;and a pair of diametrically opposed shoulders formed on the wall of theaperture and extending parallel flat surfaces of said valve stem therebylimiting the rotation thereof.
 14. The valve as defined in claim 13wherein said indexing plate is secured in said recess by retaining meansengaging said valve stem.